Tran Huy Thai

Cyperus stoloniferus Retz. is a perennial grass-like plant widely distributed in Vietnam. The composition of essential oil isolated from rhizomes has been investigated by a combination of chromatographic (Column chromatography, Gas chromatography in combination with retention indices) and spectroscopic techniques (Mass spectrometry, 13C NMR spectroscopy). Cyperene (15.8%), cyperotundone (12.9%) and α-cyperone (11.2%) were the major components. The composition of essential oil sample from this species in Vietnam differed substantially from that previously reported in China. C. stoloniferus rhizome essential oil displayed weak antibacterial activity against gram-negative bacteria, gram-positive bacteria, and yeasts.

The needle and cone essential oils of Pinus fenzeliana Hand-Mazz. (Pinus kwangtungensis Chun & Tsiang) collected in Hang Kia-Pa Co Nature Reserve, Hoa Binh province were obtained by hydrodistillation and analyzed by a combination of GC-FID, GC-MS and NMR (Gas Chromatography/Gas Chromatography-Mass Spectrometry/Nuclear Magnetic Resonance (NMR) analysis). The oil yields were 0.2% and 0.37% respectively (v/w on dry weight basis). Twenty-seven compounds were detected in both needle and cone oils, accounting for 98.0% and 98.2% of the whole composition, respectively. The main components identified in the needle oil were α-pinene (20.7%), β-pinene (11.3%), d-3-carene (32.2%), limonene (8.0%) and E-β-caryophyllene (7.1%). The cone oil contained mainly α-pinene (19.3%), β-pinene (45.4%), d-3-carene (3.5%), limonene (12.7%) and E-β-caryophyllene (3.4%). This is the first report on the chemical composition of the cone essential oil of P. fenzeliana from Vietnam.

Glyptostrobus pensilis (Staunton ex D. Don) K. Koch is a critically endangered species, native to southeastern China and also very locally found in Dak Lak Province, Vietnam. Essential oil isolated from leaves is a monoterpene-rich oil containing mainly limonene (33.3%), α-pinene (23.4%) and bornyl acetate (9.2%). The composition of G. pensilis wood oil is rather complex and the identification of individual components needed fractionation over column chromatography. The main components, identified by GC(RI), GC-MS and ¹³C NMR, were cedrol (29.3%), occidentalol (6.6%) and occidentalol isomer (5.9%).

Ophiopogon muongnhensis, a new species from Dien Bien Province, NW Vietnam, is described and illustrated. In having slenderly petioled clavate leaves it is most similar to O. griffithii originally described from NE India, but clearly distinguishable mainly by its wider (1.8–2.9 vs. 0.3–1.9 cm) leaf blades, wider (3.5–7.5 vs. 2–2.8 mm), obliquely (vs. explanately) expanded perianth lobes, and free narrowly deltoid (vs. laterally connate, linear-lanceolate) anthers. Notes on the habitat, conservation status, phenology, and taxonomic relationships with congeners were also provided.

This paper presents new data on the orchid diversity of Vietnam obtained in 2020–2022. It comprises descriptions of two species new for science (Cleisostoma tatonii and Sarcoglyphis hiepii) and descriptions of four species new for the flora of Vietnam (Cleisostoma aspersum, Gastrochilus nanus, Micropera mannii and Trichoglottis ramosa). All species found for the first time in Vietnam are morphologically slightly different from the individuals in their main distribution area. Data on accepted names, main synonyms, etymology (for newly described species), morphological description, studied specimens, ecology, phenology and distribution, conservation status assessment, brief taxonomic notes, and illustrations are provided for each species listed.

Illigera trifoliata ssp. cucullata (Merr.) Kubitzki (Hernandiaceae) is a liana distributed mainly in the tropical regions of Asia. Nothing is known on the phytochemicals produced by this species. Oil samples have been isolated from leaves, and stems, and analyzed by combination of chromatographic and spectroscopic techniques [GC(FID), GC-MS and 13C NMR]. The compositions of leaf and stem oils were dominated by a-phellandrene (25.8 and 29.2%), a-pinene (26.0 and 9.5%) and b-phellandrene (12.8 and 15.8%), followed by limonene (5.5 and 8.1%) and b-pinene (7.5 and 3.0%). The stem essential oil from Illigera trifoliata ssp. cucullata exhibited antibacterial activity against Bacillus subtilis and Escherichia coli with MIC values of 4000 μg/mL and IC50 values of 1824,56 ±136 and 2666,66 ±257 μg/mL, respectively.

This paper presents new data on the orchid diversity of Vietnam obtained in 2015–2021. It contains descriptions of three new species (Cleisostoma furcatum, Malleola micrantha, Schoenorchis hungii), one new variety (Chiloschista parishii var. minutiflora) and one new form (Cleisostoma furcatum forma albiflora). Additionally six species, Ascocentropsis malipoensis, Chiloschista sweelimii, Pomatocalpa undulatum, Trachoma rhopalorrhachis, Trichoglottis maculata, and Uncifera acuminata are newly recorded for Vietnam. The paper also provides an amended description of a very rare and poorly known species, Cleisostoma equestre. All studied taxa belong to subtribe Aeridinae (tribe Vandeae, subfamily Epidendroideae). The accepted plant name, main synonyms, data on type specimens, ecology, phenology and distribution, estimated IUCN Red List status, studied specimens, brief taxonomic notes, and illustrations are provided for each species listed.

A new species, Vanilla cardinalis (Orchidaceae, Vanilloideae) discovered in southern Vietnam (Phu Yen Province, Song Hinh District) is described and illustrated. Data on ecology, phenology, distribution, and estimated IUCN Red List conservation status of the new species are provided. Differences of V. cardinalis from its morphologically similar congeners are briefly discussed. Additionally, a checklist of the genus Vanilla and the morphologically similar Miguelia in Vietnam is presented.